in src/axis/axis.ts [1307:1332]
export function combineDomain(forcedDomain: any[], domain: any[], ensureDomain?: powerbi.NumberRange): any[] {
let combinedDomain: any[] = domain ? [domain[0], domain[1]] : [];
if (ensureDomain) {
if (combinedDomain[0] == null || ensureDomain.min < combinedDomain[0])
combinedDomain[0] = ensureDomain.min;
if (combinedDomain[1] == null || ensureDomain.max > combinedDomain[1])
combinedDomain[1] = ensureDomain.max;
}
let domainBeforeForced: any[] = [combinedDomain[0], combinedDomain[1]];
if (forcedDomain && forcedDomain.length === 2) {
if (forcedDomain[0] != null) {
combinedDomain[0] = forcedDomain[0];
}
if (forcedDomain[1] != null) {
combinedDomain[1] = forcedDomain[1];
}
if (combinedDomain[0] > combinedDomain[1]) {
combinedDomain = domainBeforeForced; // this is invalid, so take the original domain considering the values and the reference line
}
}
return combinedDomain;
}